Stretchable silver@CNT-poly(vinyl alcohol) films with efficient electromagnetic shielding prepared by polydopamine functionalization

Cellulose Nanocrystal Stabilized Liquid Metal Pickering Emulsion as Photothermal and Conductive Direct-Writing Ink

Gallium-based liquid metal (LM) has attracted great attention for constructing flexible electronic devices due to its excellent deformability and electrical conductivity. However, its large surface tension makes it difficult to be uniformly dispersed in polymers, which severely limits its wide applications. Hence, a surfactant-free approach is proposed to prepare stable LM microspheres against precipitation and coalesce by facile ultrasonication via cellulose nanocrystal (CNC) stabilized LM-in-water Pickering emulsion (PE), where CNCs are employed as Pickering emulsifiers due their partial wettability with both LM and water phases, strong electrostatic adsorption and hydrogen bonding interactions with LM. So far, reports about LM PE and CNC-stabilized inorganic material PE are still rare. CNC/LM PE is employed as direct-writing inks on various substrates for delicate patterns. The pristine CNC/LM patterns show excellent photothermal conversion due to localized surface plasma resonance effect of CNC/LM microspheres. After activation by friction sintering, the LM patterns are highly electric conductive (1666.7 S m-1) due to the formation of LM connection. The activated LM patterns also displayed excellent Joule heating (83.2 °C at 0.9 V) and electromagnetic interference (EMI) shielding ability (585.7 dB mm-1) in X-band range.

Cellulose-enhanced MoS2 bifunctional hydrogel for efficient methylene blue degradation, human body sensing, and recyclability

In this study, the dispersion behavior of MoS₂ in ionic liquids (ILs) with varying alkyl chain lengths was the primary focus of investigation, followed by the design of a novel PAM/SMA/CMC/PDA@MoS2 hydrogel. By optimizing the concentrations of CMC and PDA@MoS2, a bifunctional hydrogel with both sensing and catalytic functions was successfully developed. Mechanical tests revealed that the PAM/SMA/CMC0.06/0.09PDA@MoS2 hydrogel exhibited exceptional mechanical properties, with stress (505.24 kPa), strain (2333.34 %), elastic modulus (20.17 kPa), and toughness (3990.97 kJ/m3). Furthermore, the hydrogel demonstrated superior sensing performance, characterized by high sensitivity (GF = 7.67) and a rapid response time (148 ms) across a wide strain range. These properties enable precise monitoring of physiological movements, coupled with long-term cyclic stability, positioning it as a versatile material for sensors and electrodes. Subsequently, in situ stabilized silver nanoparticles (Ag NPs) were used as a template for the catalytic degradation of methylene blue (MB) using discarded human motion monitoring hydrogels. The degradation followed first-order kinetics (k = 0.54 min-1 at 25 °C) with 85 % efficiency sustained over 10 cycles, demonstrating significant stability and recyclability. This strategy integrates sensor recycling with Ag NPs based dye degradation, addressing environmental concerns and highlighting its potential in sustainable applications.

Synthesis and characterization of surface modified MWCNTs reinforced PVA composite films

Polymers have been ruling the packaging industry for decades due to their versatility, easy manufacturability, and low cost. The overuse of non-biodegradable plastics in food packaging has become a serious environmental concern. Multi-walled carbon nanotube (MWCNT) reinforced nanocomposites have exceptional electrical, thermal, and mechanical properties. However, a major difficulty in the synthesis of CNT-reinforced nanocomposites is the nanotube agglomeration, which results in poor dispersion and less interfacial bonding between reinforcements and matrix, limiting its advantages. Although acid treatment is effective, strong acids, treatment timing, and sonication power can lead to nanotube damage. This study introduces a novel approach to enhance PVA nanocomposite films' mechanical, thermal, optical, and antibacterial performance using polydopamine-coated CNTs, which are more effective than pristine or acid-treated CNTs, making them promising for food packaging applications. Pristine CNT reinforced polyvinyl alcohol (PVA) nanocomposite films were fabricated with varying concentrations of CNTs (0 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt%, and 2.0 wt%). These samples underwent mechanical, thermal, and optical characterization for the optimization of CNTs' concentration in the PVA matrix. Then the optimized amount of acid-treated and polydopamine-coated CNTs was used to fabricate PVA/CNT films. The mechanical, thermal, and optical characteristics of the resultant films were investigated. It was found that the polydopamine coating on CNTs improved the mechanical, thermal, and optical properties of the films as compared to those of pure PVA, PVA/pristine CNT, and PVA/acid-treated CNT films. Moreover, the resultant film also demonstrated good antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) in comparison to pure PVA.

Mechanical Properties and Electromagnetic Interference Shielding of Carbon Composites with Polycarbonate and Acrylonitrile Butadiene Styrene Resins

As environmental pollution becomes a serious concern, considerable effort has been undertaken to develop power devices with minimal production of carbon dioxide (CO₂) and exhaust gases. Owing to this effort, interest in technologies related to hybrid and electric products that use fuel cells has been increasing. The risk of human injuries owing to electromagnetic waves generated by electrical and electronic devices has been also rising, prompting the development of mitigating technologies. In addition, antistatic devices for protecting operators from static electricity have also been considered. Therefore, in this study, we investigated the development of thermoplastic carbon composites containing carbon fibers (CFs) and carbon nanotubes (CNTs). Ultimately, materials with improved mechanical properties (e.g., flexural, impact, and tensile strength properties of about +61.09%, +21.44%, +63.56%, respectively), electromagnetic interference (EMI) shielding (+70.73 dB), and surface resistivity (nearly zero) can be developed by impregnating CFs and CNTs with polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) resins, respectively. The total average mechanical properties of PC and ABS composites increased by 24.35% compared with that of ABS composites, while that of PC composites increased by 32.86% with that of PC and ABS composites. Therefore, in this study, we aimed to develop carbon composites, to take advantage of these thermoplastic resins.

Preparation of carbon black/silicone rubber composites with large-area-homogeneous-low electrical-resistance used as electroplating matrix

Conductive carbon black (CCB) is an important filler in stretchable conductive silicone rubber (CSR) composites. However, due to the active oxygen-containing groups on CCB, introducing it into silicone rubber (SR) may cause SR to not completely cure. Surface modification of CCB may ease the problem but at the cost of reducing the electrical conductivity of pristine CCB. In this work, the curing and crosslinking performance of CCB/SR is detected in detail, the hydroxyl groups (-OH) carried by CCB can react with the silicon-hydrogen group (Si-H) with the existence of Pt catalyst, causing insufficiency of the hydrosilylation reaction thus hindering the solidifying process of silicon rubber. To take advantage of this reaction, more hydrogen silicone oil (PHMS) possessing silicon-hydrogen bonds is introduced into the system to improve the curing degree as well as fix the CCB in the crosslinked network. Due to the lock-in effect of CCB, the resistance of CSR samples is stable after several hundred bending cycles, and the composite's tensile strength is three times that of the pure SR samples. Besides, the size of the composites can expand to dozens of centimeters or even a few meters with uniform electric conductivity. This composite has resistance as low as 10.20 Ω and is suitable to make electroplating mold, and a rapid plating rate of 2.4 mm/24 h can be achieved. Meanwhile, the overall properties make this CSR composite have potential applications in mold manufacture, flexible electronics, and other related fields.

Recent Advances in Design Strategies and Multifunctionality of Flexible Electromagnetic Interference Shielding Materials

With rapid development of 5G communication technologies, electromagnetic interference (EMI) shielding for electronic devices has become an urgent demand in recent years, where the development of corresponding EMI shielding materials against detrimental electromagnetic radiation plays an essential role. Meanwhile, the EMI shielding materials with high flexibility and functional integrity are highly demanded for emerging shielding applications. Hitherto, a variety of flexible EMI shielding materials with lightweight and multifunctionalities have been developed. In this review, we not only introduce the recent development of flexible EMI shielding materials, but also elaborate the EMI shielding mechanisms and the index for "green EMI shielding" performance. In addition, the construction strategies for sophisticated multifunctionalities of flexible shielding materials are summarized. Finally, we propose several possible research directions for flexible EMI shielding materials in near future, which could be inspirational to the fast-growing next-generation flexible electronic devices with reliable and multipurpose protections as offered by EMI shielding materials.